The present invention generally relates to global communication interrupt control systems, and more particularly to a global communication interrupt control system which is used when making a communication between a real machine system and a virtual machine system using a global communication function of a shared memory.
In this specification, the global communication function will hereinafter also be referred to as a global signal processor (GSIGP).
A large computer system made up of a plurality of computer systems has various applications. In one example of such applications, a system storage unit which is provided as an external storage is shared by a real machine of one computer system and a guest virtual machine (guest VM) which is a virtual machine of another computer system. In this case, effective utilization of a central processing unit (CPU) by the virtual machine can be realized, while realizing a high-speed hot stand-by and a high-speed process by the plurality of computer systems.
When realizing a communication between the real machine and the virtual machine of different computer systems using the global signal processor (GSIGP), hardware is provided to hold a communication interrupt request at the virtual end and to cancel the interrupt hold when the interrupt is reflected to the virtual machine. The interrupt hold state can constantly be monitored by hardware of the real machine which is the source of the interrupt request. If the interrupt hold of the interrupt request is cancelled, it is determined that the interrupt is reflected or sent to the virtual machine and the operation continues to a next process.
If the communication interrupt is issued from the real machine of one computer system to the virtual machine of another computer system, a guest VM which is provided as the virtual machine is put into an operable state by a control program (CP) which is known as a virtual machine (VM) monitor program. The interrupt is first reflected to the control program (CP), and is thereafter reflected to the guest VM. However, the interrupt hold is cancelled at the stage when the interrupt is reflected to the control program (CP). For this reason, although the interrupt is actually not yet reflected to the guest VM, it appears to the source of the interrupt request as if the interrupt has been reflected to the guest VM, and it is desirable to improve the system in this respect.
On the other hand, if the global signal processor (GSIGP) function were used by the real machine system to realize an initial program load (IPL) function of a virtual machine system, the IPL would be made to the control program (CP) and not to the guest VM. As a result, it would be impossible in this case to carry out an accurate process with respect to the guest VM. Moreover, there is a problem in that the real machine system cannot be aware of the actual state of the virtual machine system.